Richard Feynman, a man about as difficult to bamboozle on
scientific topics as any who ever lived, remarked
in an interview (p. 180) in 1987, a year before his death:

…I think all this superstring stuff is crazy
and it is in the wrong direction. … I don't like
that they're not calculating anything. I don't like that
they don't check their ideas. I don't like that for
anything that disagrees with an experiment, they cook up
an explanation—a fix-up to say “Well, it still
might be true.”

Feynman was careful to hedge his remark as being that of
an elder statesman of science, who collectively have a history of foolishly
considering the speculations of younger researchers to
be nonsense, and he would have almost certainly have opposed
any effort to cut off funding for superstring research, as
it might be right, after all, and should be pursued in
parallel with other promising avenues until they make
predictions which can be tested by experiment, falsifying
and leading to the exclusion of those candidate theories whose predictions
are incorrect.

One wonders, however, what Feynman's reaction would have
been had he lived to contemplate the contemporary scene
in high energy theoretical physics almost twenty years
later. String theory and its progeny still have
yet to make a single, falsifiable prediction which can
be tested by a physically plausible experiment. This isn't
surprising, because after decades of work and tens of thousands
of scientific publications, nobody really knows, precisely,
what superstring (or M, or whatever) theory really is; there is
no equation, or set of equations from which one can draw
physical predictions. Leonard Susskind, a co-founder of string
theory, observes ironically in his book
The
Cosmic Landscape (March 2006), “On this
score, one might facetiously say that String Theory is the ultimate
epitome of elegance. With all the years that String Theory has
been studied, no one has ever found a single defining equation!
The number at present count is zero. We know neither what the
fundamental equations of the theory are or even if it has
any.” (p. 204). String theory might best be
described as the belief that a physically correct
theory exists and may eventually be discovered by the research
programme conducted under that name.

From the time Feynman spoke through the 1990s, the goal toward
which string theorists were working was well-defined: to find a
fundamental theory which reproduces at the low energy limit the
successful results of the standard model of particle physics, and
explains, from first principles, the values of the many (there are
various ways to count them, slightly different—the author gives
the number as 18 in this work) free parameters of that theory, whose
values are not predicted by any theory and must be filled in by
experiment. Disturbingly, theoretical work in the early years of this
century has convinced an increasing number of string
theorists (but not all) that the theory (whatever it may turn out to be), will not
predict a unique low energy limit (or “vacuum state”), but
rather an immense “landscape” of possible universes, with
estimates like 10100 and 10500 and even more
bandied around (by comparison, there are only about 1080
elementary particles in the entire observable universe—a
minuscule number compared to such as these). Most of these possible universes
would be hideously inhospitable to intelligent life as we know and
can imagine it (but our imagination may be limited), and hence it is
said that the reason we find ourselves in one of the rare universes which contain
galaxies, chemistry, biology, and the National Science Foundation is
due to the
anthropic principle: a statement, bordering on
tautology, that we can only observe conditions in the universe which
permit our own existence, and that perhaps either in a
“multiverse” of causally disjoint or parallel realities,
all the other possibilities exist as well, most devoid of observers,
at least those like ourselves (triune glorgs, feeding on bare colour
in universes dominated by quark-gluon plasma would doubtless deem
our universe unthinkably cold, rarefied, and dead).

But adopting the “landscape” view means abandoning the
quest for a theory of everything and settling for what
amounts to a “theory of anything”. For even if
string theorists do manage to find one of those 10100
or whatever solutions in the landscape which perfectly reproduces
all the experimental results of the standard model (and note that
this is something nobody has ever done and appears far out of reach,
with legitimate reasons to doubt it is possible at all), then there
will almost certainly be a bewildering number of virtually identical
solutions with slightly different results, so that any plausible
experiment which measures a quantity to more precision or discovers
a previously unknown phenomenon can be accommodated within the theory simply
by tuning one of its multitudinous dials and choosing
a different solution which agrees with the experimental results. This
is not what many of the generation who built the great intellectual
edifice of the standard model of particle physics would have considered
doing science.

Now if string theory were simply a chimæra being pursued by a small
band of double-domed eccentrics, one wouldn't pay it much
attention. Science advances by exploring lots of ideas which
may seem crazy at the outset and discarding the vast majority
which remain crazy after they are worked out in more
detail. Whatever remains, however apparently crazy, stays in the box
as long as its predictions are not falsified by experiment. It would
be folly of the greatest magnitude, comparable to attempting to centrally
plan the economy of a complex modern society, to try to guess in advance, by
some kind of metaphysical reasoning, which ideas were worthy of
exploration. The history of the S-matrix or “bootstrap”
theory of the strong interactions recounted in chapter 11 is an
excellent example of how science is supposed to work. A beautiful
theory, accepted by a large majority of researchers in the field,
which was well in accord with experiment and philosophically
attractive, was almost universally abandoned in a few years after the success of the
quark model in predicting new particles and the stunning
deep inelastic scattering results at SLAC in the 1970s.

String theory, however, despite not having made a single testable
prediction after more than thirty years of investigation, now seems
to risk becoming a self-perpetuating intellectual monoculture in
theoretical particle physics. Among the 22 tenured professors of
theoretical physics in the leading six faculties in the United
States who received their PhDs after 1981, fully twenty
specialise in string theory (although a couple now work on the
related brane-world models). These professors employ graduate students
and postdocs who work in their area of expertise, and when a faculty
position opens up, may be expected to support candidates working
in fields which complement their own research. This environment creates
a great incentive for talented and ambitious students aiming for one
the rare permanent academic appointments in theoretical physics to
themselves choose string theory, as that's where the jobs are.
After a generation, this process runs the risk of operating on its
own momentum, with nobody in a position to step back and admit that
the entire string theory enterprise, judged by the standards of
genuine science, has failed, and does not merit the huge human investment
by the extraordinarily talented and dedicated people who are pursuing it,
nor the public funding it presently receives. If Edward Witten believes
there's something still worth pursuing, fine: his self-evident genius and
massive contributions to mathematical physics more than justify supporting
his work. But this enterprise which is cranking out hundreds of PhDs and
postdocs who are spending their most intellectually productive years learning
a fantastically complicated intellectual structure with no grounding whatsoever
in experiment, most of whom will have no hope of finding permanent employment
in the field they have invested so much to aspire toward, is much more difficult
to justify or condone.

The problem, to state it in a manner more inflammatory than the measured
tone of the author, and in a word of my choosing which I do not believe
appears at all in his book, is that contemporary academic research in
high energy particle theory is corrupt. As is usually the case
with such corruption, the root cause is socialism, although the look-only-left
blinders almost universally worn in academia today hides this from most
observers there. Dwight D. Eisenhower, however, twigged to it quite early.
In his farewell address
of January 17th, 1961, which academic collectivists endlessly cite for its
(prescient) warning about the “military-industrial complex”, he
went on to say, although this is rarely quoted,

In this revolution, research has become central; it also becomes more
formalized, complex, and costly. A steadily increasing share is
conducted for, by, or at the direction of, the Federal government.

Today, the solitary inventor, tinkering in his shop, has been over
shadowed by task forces of scientists in laboratories and testing
fields. In the same fashion, the free university, historically the
fountainhead of free ideas and scientific discovery, has experienced a
revolution in the conduct of research. Partly because of the huge
costs involved, a government contract becomes virtually a substitute
for intellectual curiosity. For every old blackboard there are now
hundreds of new electronic computers.

The prospect of domination of the nation's scholars by Federal
employment, project allocations, and the power of money is ever
present and is gravely to be regarded.

And there, of course, is precisely the source of the corruption. This
enterprise of theoretical elaboration is funded by taxpayers, who
have no say in how their money, taken under threat of coercion, is
spent. Which researchers receive funds for what work is largely
decided by the researchers themselves, acting as peer review panels.
While peer review may work to vet scientific publications, as soon as
money becomes involved, the disposition of which can make or break
careers, all the venality and naked self- and group-interest which has
undone every well-intentioned experiment in collectivism since Robert
Owen comes into play, with the completely predictable and tediously
repeated results. What began as an altruistic quest driven by
intellectual curiosity to discover answers to the deepest questions
posed by nature ends up, after a generation of grey collectivism, as a
jobs program. In a sense, string theory can be thought of
like that other taxpayer-funded and highly hyped program, the space
shuttle, which is hideously expensive, dangerous to the careers of
those involved with it (albeit in a more direct manner), supported by
a standing army composed of some exceptional people and a mass of the
mediocre, difficult to close down because it has carefully cultivated a
constituency whose own self-interest is invested in continuation of
the program, and almost completely unproductive of genuine science.

One of the author's concerns is that the increasingly apparent
impending collapse of the string theory edifice may result in the
de-funding of other promising areas of fundamental physics research.
I suspect he may under-estimate how difficult it is to get rid of
a government program, however absurd, unjustified,
and wasteful it has become: consider the space shuttle, or mohair
subsidies. But perhaps de-funding is precisely what is needed to
eliminate the corruption. Why should U.S. taxpayers be spending
on the order of thirty million dollars a year on theoretical physics
not only devoid of any near- or even distant-term applications, but also
mostly disconnected from experiment? Perhaps if theoretical physics
returned to being funded by universities from their endowments and
operating funds, and by money raised from patrons and voluntarily contributed
by the public interested in the field, it would be, albeit a much
smaller enterprise, a more creative and productive one. Certainly
it would be more honest. Sure, there may be some theoretical breakthrough
we might not find for fifty years instead of twenty with
massive subsidies. But so what? The truth is out there, somewhere
in spacetime, and why does it matter (since it's unlikely in the extreme
to have any immediate practical consequences) how soon we find it,
anyway? And who knows, it's just possible a research programme
composed of the very, very best, whose work is of such obvious merit
and creativity that it attracts freely-contributed funds, exploring
areas chosen solely on their merit by those doing the work, and driven
by curiosity instead of committee group-think, might just get there
first. That's the way I'd bet.

For a book addressed to a popular audience which contains not a single equation,
many readers will find it quite difficult. If you don't follow these matters
in some detail, you may find some of the more technical chapters rather
bewildering. (The author, to be fair, acknowledges this at the outset.)
For example, if you don't know what the hierarchy problem is, or why it is
important, you probably won't be able to figure it out from the discussion
here. On the other hand, policy-oriented readers will have little difficulty
grasping the problems with the string theory programme and its probable
causes even if they skip the gnarly physics and mathematics. An entertaining
discussion of some of the problems of string theory, in particular the
question of “background independence”, in which the string
theorists universally assume the existence of a background spacetime
which general relativity seems to indicate doesn't exist, may be found
in Carlo Rovelli's "A Dialog on
Quantum Gravity". For more technical details, see Lee Smolin's
Three Roads to Quantum Gravity.
There are some remarkable factoids in this book, one of the most stunning
being that the proposed TeV class muon colliders of the future will produce
neutrino (yes, neutrino) radiation which is dangerous to
humans off-site. I didn't believe it either, but
look here—imagine the
sign: “DANGER: Neutrino Beam”!

A U.S. edition is scheduled for
publication at the end of September 2006.
The author has operated the Not
Even Wrong Web log since 2004; it is an excellent source for news
and gossip on these issues. The unnamed “excitable … Harvard
faculty member” mentioned on p. 227 and elsewhere is
Luboš Motl (who is,
however, named in the acknowledgements), and whose
own Web log is always worth checking out.